JPH0141187Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electric heating pipe equipped with a heater that generates heat when energized in a water guide pipe or the like that requires freezing prevention.

Conventional electric heating pipes of this type include ones in which a heater wire 2 is spirally wound around the outer periphery of a pipe body 1, as shown in FIG. 1, and tape-shaped heaters 4 attached vertically as shown in FIG. Both of them heat the pipe body 1 indirectly by energizing the heaters 1 and 4 to generate heat.

In addition, 3 is a heat insulation layer.

However, first of all, in the case of wrapping two heater wires, the length of wrapping the heater wire 2 around the pipe body inevitably becomes large, and since the heater wire is wound around the pipe that has already been installed,
The drawback was that on-site facility work required a great deal of effort.

In addition, even in the case of the vertical attachment method of the tape-shaped heater 4, binding and gluing work is required to fix the heater 4 to the pipe body, which has the disadvantage that it requires as much time and effort at the on-site facility work as the above-mentioned method. Ta.

Furthermore, in any of these methods, a gap inevitably occurs between the pipe body and the heater attached to it, and there is a tendency for so-called uneven heating to occur, where there are parts that are significantly heated and parts that are not sufficiently heated. The disadvantage is that the amount of power generated by the heater is increased more than necessary in order to sufficiently heat the parts to which no particles are attached.

The present invention solves the above-mentioned drawbacks of the conventional technology,
The object of the present invention is to provide an electric heating pipe of this type which is extremely easy to install at the site of a facility, can be heated uniformly, and does not require an unnecessarily large amount of heating power.

That is, the electric heating pipe of the present invention has an extruded coating layer of semiconductive rubber or semiconductive plastic that is continuously and tightly formed in the circumferential direction and length direction of the pipe body, and The covering layer has a plurality of conductive wires embedded along its length and distributed at equal intervals in the circumferential direction.

A more detailed description will be given below with reference to the accompanying drawings.

FIG. 3 shows a preferred example of the electric heating pipe of the present invention.

In the figure, reference numeral 6 denotes an extruded coating layer of semiconductive rubber or plastic, which is extruded in close contact with the outside of the pipe body 1 in its circumferential and longitudinal directions.

A plurality of conductive wires 5 are embedded in the semiconductive extruded coating layer 6 along the length direction while being distributed at equal intervals in the circumferential direction, and these conductive wires 5 are connected to a heating power source and energized. By doing so, the semiconductive extruded coating layer 6 is made to generate heat due to its resistance.

The semiconductive layer 6 can be made to have the desired conductivity by mixing conductive powder such as carbon black or graphite into a resin made of rubber such as butyl rubber, chloroprene, silicone rubber, or plastic such as polyethylene or vinyl. Apply a material that gives the

The desired semiconductive layer is formed by extrusion coating such a semiconductive resin on the outer periphery of the pipe body, but during the extrusion coating, the conductive wire 5 is mixed into an extruder and extruded together with the resin. By this,
Conductive wires can be embedded within the extruded coating layer.

Such an extruded coating layer may be vulcanized or crosslinked for the purpose of improving heat resistance properties.

7 is a protective layer made of vinyl or the like, which serves both as electrical insulation and thermal insulation.

It is practical to have two to four conducting wires 5, and FIG. 4 shows an example of an electric heating pipe having such a number.

When there are two conductive wires 5 as in A, they are embedded in the semiconductive extruded coating layer 6 at intervals of 180° in the circumferential direction thereof.

In the case of three conductive wires 5 as in B, they are embedded in the semiconductive extruded coating layer 6 at intervals of 120° in the circumferential direction, and as in C, four conductive wires 5 are embedded. In the case of books, they are embedded in the semiconductive extruded coating layer 6 at intervals of 90° in the circumferential direction thereof.

The electric heating pipe of the present invention configured in this way is
By extruding the semiconductive extruded coating layer 6 that embeds the conductor 5 onto the bare pipe at the factory, it can be handled in the same way as a normal pipe without the need to wrap a heater around it at the facility site. It can be easily installed by following these steps.

When the buried conducting wire 5 is connected to a heating power source, the entire circumference of the pipe body 1 is heated evenly and uniformly by the heat generated by the semiconductive extruded coating layer 6 that is tightly coated.

FIG. 5 shows an example in which various different circuits are formed depending on the number of conducting wires 5.

In case A, two conductors 5 are connected to the single-phase transformer 8, A and B. In case B, three conductors 5 are connected to the three-phase transformer 8, A, B, and C. An example is shown, and in the case of C, the four conductors are divided into two wires and each wire is connected to the single-phase transformer 8 with wires A, B, and
Here is an example of A′ and B′. In both examples, the other end of the conductive wire is open.

9 indicates the equivalent resistance of the semiconductive extruded coating layer.

Note that if the conductive wire 5 is thick and it becomes difficult to bend the pipe if it is buried in the semiconductive extruded coating layer, the conductive wire 5 may be kept in a parallel state while
It is preferable to form it into a spiral and embed it in the semiconductive extruded coating layer.

Alternatively, the conducting wire itself may be made into a spiral body or may be corrugated, so that it can follow the expansion and contraction of the semiconductive coating layer due to bending of the pipe.

As explained above, the electric heating pipe of the present invention can be installed extremely easily on-site without the need for labor such as winding a heater. Since it is formed in close contact with the outer surface of the coil in both the circumferential direction and the length direction, it can be heated evenly and evenly, and there is no gap that reduces heat transfer, making it possible to carry out efficient electrical heating and economical. be advantageous to Furthermore, according to the electric heating pipe of the present invention, a plurality of conductive wires are embedded in the semiconductive current heating layer along its length while being distributed at equal intervals in the circumferential direction of the heating layer. Therefore, the current-carrying heat generating layer can form multiple current-carrying zones separated by these multiple conductors, and most of one band may be cut off by a tear or the like and cannot conduct current. Even if the other band continues to generate heat through current, it is possible to perform sound current heating. Problems in use such as the inability to energize or extremely high heat due to energization heating are solved, and the advantageous energization heating can withstand severe use, and the practical effects are enormous. .

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams showing an example of a conventional electric heating pipe, Figure 3 is an explanatory diagram showing an embodiment of the electric heating pipe of the present invention, and Figure 4 A, B, and C are illustrations of the electric heating pipe of the present invention. FIGS. 5A, 5B, and 5C are explanatory cross-sectional views showing different examples of embedding conductive wires, and FIGS. 1: pipe body, 5: conducting wire, 6: extruded coating layer of semiconductive rubber or semiconductive plastic.

Claims (1)

[Scope of utility model registration request] On the outside of the pipe body, there is an extruded coating layer of semiconductive rubber or semiconductive plastic that is continuously and closely formed in the circumferential direction and lengthwise direction, and the extruded coating layer has a An electric heating pipe characterized by having a plurality of conductive wires buried along its length and distributed at equal intervals.